Variable condenser



Dec. 6, 1927. 1,651,975

r -H. M. SPECHT v VARIABLE CONDENSER Filed Dec. 19. 1923 2 Sheets-Sheet1 i )J INVENTOR Dec. 6, 1927.

1,651,975 H. M SPECHT VARIABLE CONDENSER iled Dec. 19. 1925 2Sheets-Sheet 2 Q 7 v M INK: VENTOR 7 BY M M between the stator plates itthey are slightly Patented Dec. 6, 1927.

UNITED STATES PATENT OFFICE.

HARRY MORTIMER SPECHT, OF PELHAM, NEW YORK.

VARIABLE oonnnnsnn.

Application filed. December 19, 1923. Serial No. 681,483.

This invention relates to a variable condenser and the novelty consistsin the adaptation and arrangement of parts as will be more fullyhereinafter pointed out. i There is a tremendous demand among thoseusing radio receiving outfits for an efficient variable condenser whichwill give service at all times. Variable condensers now on the marketare made up of two series of flat plates, one series being rigidlysecured in position and called a stator series and the second seriesbeing rigidly secured to a rotatable shaft and adapted to rotate intoposition between the stator plates,

which series is known as the rotor series;

These plates are usually madeof aluminum and although absolutelyefficientin handling E. M. F. they do not stand up in'service as theyare readily bent'out of exact position and more readily this applies tothe rotor plates so that-in rotatingto the position in out of true theywill cause a slight contact which absolutely destroys the efliciency ofthe variable condenser.

My device overcomes this weakness and fault in the variable condensersnow on the market by constructing the stator and rotor plates in such aform that they will have substantial strength so that they will noteasilyor readily bend out of shape, but will withstand all ordinaryusage and ordinary abusage, to which they may be subjected in the handsof the amateur radio operator.

My variable condenser also is adapted to sul' s:tantiall y increase theamount of plate space for holding the electrons and protons, doing so ina reducedspace so that it is more highly e'tlicient handling E. M. F.than the vari able condensers now on the market.

My device also adapted to contain a variometer within itself so as toeffect econoiny of space in operation. It likewise has a vernieradjustment so that the finest adjustments can be attained with my deviceand the combination results in a wider range of adjustments than ispossible on any variable condenser heretofore known.

Referring to the drawings, Fig. 1 is a perspective of the exterior of mydevice;

Fig. 2 is a vertical section through the center of Fig. 1;

Figs. 3 and 4 are details of the shaft constructions used in my device;and

Fig. 5 is a perspective of my device showing the rotor space ofconcentric semi-spherical cup members partially interleaved with thestator series and part of the same being broken away in order to showthis inter leaving, and also showing a vernier in combination therewithin partial cross section.

In'thedrawings 6 is a tubular rotatable shaft to which a series ofconcentric semispherical cup members 7 are rigidly secured so as torotate therewith. A tubular shaft 8 is adapted to be mounted over theshaft 6 and a second series of concentric se1ni-spher ical cup members 9is rigidly secured to said shaft 8. The tubular shaft 8 hassemi-circular cut out portions 10 through which the series ofcon'centricsemi-spherical cup members 7 are adapted to pass, said cup me1nbers 7being insulated from possible'contact with said shaft 8 and saidcupmembers 9 beinginsulated against-possible contact with shaft 6, and theair serving as the dielectric as iii-the usual flat plate constructionof variable condensers. A shaft 20 is mounted in shaft 6 and is brokenoff at the outer end where it is controlled as to independent rotationand is connected to the E. M. F. A suitable connecting terminal 11 issecured to the shaft 6 so that connection with the usual source of powermay be effected and a suitable connecting terminal'lQ is secured to theshaft 8 so that a suitable connection can be made to the source of powerby this means.

A variometer 13 of usual construction may be mounted in my variablecondenser with a rotor portion mounted to turn with shaft 20, as shownin Fig. 2.

A control means of usual construction having a regular adjustment dial15 rigidly secured to the shaft 6 and a fine adjustment or Vernier dial16 is adapted to be mounted as shown in Fig. 5, having a plate 18connected through a contact pin 17 to the series of concentricsemi-spherical cup members 9 and the second plate 19 being connecteddirectly through the shaft 6 to the other series of concentricsemi-spherical cup members 7.

The concentric series of semi-spherical cup members 9 is a stator seriesas it does not turn, but is rigidly secured in the fixed position, asindicated, being connected with the tubular shaft 8 which in turn isconnected to the electrical circuit by means of connecting terminal 12.The series of concentric semi-spherical cup members 7 is a rotor series,which, being rigidly connected to the shaft 6 rotates from the positionshown in Fig. 2, which is the minimum capacity or open position, to aposition where all the se-- ries of concentric semi-spherical cupmembers 7 are fully interleaved within the series of semi-spherical cupmembers 9, which is the maximum capacity or closed position. Thismovement is made possible by the slots 10 which permit the rotor series7 to rotate a complete semi-circle, so as to effect this operation.

In using my variable condenser, the usual methods of operation will befollowed as the turning of shaft 6 will effect the adjustment soughtand'the adjustment of variometer 13 will be effected by turning shaft20. .The Vernier adjustments will be used through the dial 15 in theordinary adjustment and through the dial 16in making the final or fineradjustments.

I claim:

1. A variable condenser comprising a series of concentric rotorsemi-spherical cup members, a series of concentric stator semisphericalcup members and means for turn spherical cup members and means forturning said rotor cup members into and out of full interleaved relationbetween the corresponding stator cup members in combination with avariometer encased by said stator and rotor cup members and mounted onan indeendently controlled shaft and a Vernier adustment means connectedto both the stator and rotor cup members.

3. In a variable condenser the combination of a series of concentricrotor semi-spherical cup members rigidly secured to a central shaft, aseries of concentric stator semis herical cup members rigidly secured toa s otted shaft mounted over said central shaft and insulated therefromtogether with connecting terminals on each of said shafts and avariometer encased by said stator and rotor cup members and mounted onan independently controllcd shaft.

4. In a variable condenser the combination of a series of concentricrotor semi-spherical cup members rigidly secured to a central shaft, aseries of concentric stator semisplierical cup members rigidly securedto a slotted shaft mounted over said central shaft and insulatedtherefrom together with connecting terminals on each of said shafts anda variometer encased by said stator and rotor cup members and a Vernieradjustment means connected to both the stator and rotor cup members.

In testimony whereof I afiix my signature.

HARRY MORTIMER- SPECHT.

